Stock material or miscellaneous articles – Composite – Of addition polymer from unsaturated monomers
Reexamination Certificate
2001-02-05
2002-07-16
Nakarani, D. S. (Department: 1773)
Stock material or miscellaneous articles
Composite
Of addition polymer from unsaturated monomers
C428S519000, C428S520000
Reexamination Certificate
active
06420050
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to multilayer composite structures and compositions for making the same. More particularly, the present invention concerns a multilayer thermoformable composite structures having a formulated acrylic cap.
BACKGROUND OF THE INVENTION
Multilayered structures formed from blended polymers are useful in preparing parts for: the automotive industry; communications such as telephones, radio, TV, cassettes, etc.; power tools; appliances; business machines; toys; furniture; medical devices etc. When preparing multilayer structures, the layers of the structures must adhere securely to each other. If the layers of the structure do not adhere to each other a special adhesive, or in other cases a tie layer, may be used to join the layers of the multilayer structure together.
Multilayer or composite structures formed by blends of different polymer compositions are known in the prior art. Examples of such multilayer structures may be found, for example, in Chundury et al. U.S. Pat. Nos. 5,264,280, 5,374,680 and 5,385,781. Generally speaking, these patent references disclose a multilayer structure comprising an olefinic core layer and a cap layer comprising a polymer of a vinyl aromatic compound such as polystyrene.
The present invention provides a new and useful multilayer composite structure which provides the physical properties of an olefinic core layer and the glossy, scratch and chemical resistive properties of an acrylic cap layer. Furthermore, the acrylic cap layer serves to further enhance the thermoformability of the olefin or olefin blend cap layer.
SUMMARY OF THE INVENTION
The present invention provides a new and useful multilayer thermoformable structure comprising: a formulated cap layer (A) comprising at least about 50% by weight of a polymethacrylate ester, a polyacrylate ester, copolymers, and/or blends thereof; and a core layer (B) comprising from about 30% to about 100% by weight of a polyolefin. In a preferred embodiment, the formulated cap layer (A) comprises: (Ai) from about 50% to about 90% by weight of a polymethacrylate ester or polyacrylate ester polymer or their copolymers or blends thereof; (Aii) from about 0% to about 45% by weight of at least one block polymer of a vinyl aromatic monomer and an aliphatic conjugated diene, a selectively hydrogenated derivative thereof, or a selectively hydrogenated derivative thereof to which has been grafted an unsaturated carboxylic reagent or anhydride, wherein the block polymer contains up to about 50% by weight bound styrene; and (Aiii) from about 0% to about 45% by weight of at least one block polymer of a vinyl aromatic monomer and a conjugated diene, a partially hydrogenated derivative thereof, or a selectively hydrogenated derivative thereof to which has been grafted an unsaturated carboxylic reagent or anhydride, wherein the block polymer contains greater than about 60% by weight bound vinyl aromatic monomer, with the proviso that the cap layer (A) includes at least one of (Aii) or (Aiii).
In another preferred embodiment, the formulated cap layer (A) comprises: (Ai) from about 50% to about 95% by weight of a polymethacrylate ester, polyacrylate ester polymer, their copolymers, and/or blends thereof; and (Aiv) from about 5% to about 50% by weight of one or more olefin acrylate copolymers. Formulated cap layers (A) comprising blends of (Ai) and (Aiv) can also further comprise one or more of (Aii) and/or (Aiii).
The multilayer thermoformable composite structures of the present invention are useful in preparing thermoformed articles and are particularly useful in applications that require the thermoformability of an olefin and the gloss, scratch resistance and chemical resistance of an acrylic polymer. Applications for the multilayer structures of the present invention include, for example, automotive parts, plumbing fixtures and parts such as shower stalls, and appliance parts such as control panels, housings and lids; and medical applications.
The foregoing and other features of the invention are hereinafter more fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the present invention may be employed.
DETAILED DESCRIPTION
Unless the context clearly indicates otherwise, as used in the instant specification and in the appended claims, the term “olefin-containing” or “olefinic” means that the material contains one or more thermoplastic polymers derived from olefin monomers. Olefin-containing materials can be homopolymers of olefin monomers, copolymers derived in part from olefin monomers, and polyblends that contain such olefinic homopolymers and/or copolymers blended with other polymers. Olefin-containing materials of this type are sometimes referred to herein as olefin alloys. As noted above, this application claims benefit of U.S. Provisional Application Ser. No. 60/179,978, filed Feb. 3, 2000, which is hereby incorporated by reference in its entirety.
The present invention provides a new and useful multilayer thermoformable structure comprising: a formulated cap layer (A) comprising at least about 50% by weight of a polymethacrylate ester, a polyacrylate ester, copolymers, and/or blends thereof; and a core layer (B) comprising from about 30% to about 100% by weight of a polyolefin. The components of the multilayer thermoformable composite structure of the present invention, as well as the most preferred embodiments thereof, are separately discussed in greater detail below.
Formulated Cap Layer (A)
The formulated cap layer (A) comprises at least about 50% by weight of a polymethacrylate ester, a polyacrylate ester, copolymers, and/or blends thereof. In one preferred embodiment, the formulated cap layer (A) comprises: (Ai) from about 50% to about 90% by weight of a polymethacrylate ester or polyacrylate ester polymer or their copolymers or blends thereof; (Aii) from about 0% to about 45% by weight of at least one block polymer of a vinyl aromatic monomer and an aliphatic conjugated diene, a selectively hydrogenated derivative thereof, or a selectively hydrogenated derivative thereof to which has been grafted a unsaturated carboxylic reagent or anhydride, wherein the block polymer contains up to about 50% by weight bound styrene; and (Aiii) from about 0% to about 45% by weight of at least one block polymer of a vinyl aromatic monomer and a conjugated diene, a partially hydrogenated derivative thereof, or a selectively hydrogenated derivative thereof to which has been grafted a unsaturated carboxylic reagent or anhydride, wherein the block polymer contains greater than about 60% by weight bound vinyl aromatic monomer; with the proviso that the formulated cap layer (A) includes at least one of (Aii) or (Aiii), and preferably both.
In another preferred embodiment, the formulated cap layer (A) comprises: (Ai) from about 50% to about 95% by weight of a polymethacrylate ester or polyacrylate ester polymer or their copolymers or blends thereof; and (Aiv) from about 5% to about 50% by weight of one or more olefin acrylate copolymers. A formulated cap layer (A) comprising a blend of (Ai) and (Aiv) can also further comprise (Aii) and/or (Aiii).
Polyacrylate Ester Polymers, Copolymers, and or Blends Thereof (Ai)
As noted above, in the preferred embodiment the formulated cap layer (A) comprises at least about 50% by weight, and preferably from about 50%, or from about 60% to about 95%, or to about 80% by weight of (Ai) a polymethacrylate ester, a polyacrylate ester polymer, or copolymers and/or blends thereof. Preferably, (Ai) comprises one or more acrylic polymers formed from methyl methacrylate (MMA) monomer. It will be appreciated that various acrylate comonomers may be copolymerized with MMA to lower the glass transition temperature (T
g
) of the acrylic polymer and thus confer some degree of flexibility to the formulated cap layer (A). Suitable acrylate comonomers are those, when polyme
Birch Timothy W.
Scheibelhoffer Anthony S.
Ferro Corporation
Nakarani D. S.
Rankin, Hill Porter & Clark LLP
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